Impairment of corneal epithelial barrier function in diabetics.

Corneal epithelial permeability was determined using an automatic fluorophotometer in 80 consecutive diabetic patients. The corneal epithelium, which is the most important part of the corneal diffusion barrier, showed a significant increase of permeability to watery, ionic substances (natrium fluorescein). The permeability was increased 5.4 times in comparison with nondiabetic individuals and a distinct correlation of increased permeability with the presence and duration of retinal nonperfusion areas was observed.